Table 2.
Time-averaged characteristics of peritoneal dialysis patients stratified by four serum ferritin concentration groups.
| Characteristics | Ferritin (ng/mL) | ||||
|---|---|---|---|---|---|
| < 300 | 300–499 | 500–799 | ≥ 800 | p value | |
| n | 1919 | 1134 | 778 | 525 | |
| Age (years) | 49.6 (14.4) | 52.0 (14.2) | 54.0 (14.5) | 55.4 (15.8) | < 0.0001 |
| Age group | |||||
| 20–39 years, n (%) | 479 (24.9) | 217 (19.1) | 127 (16.3) | 105 (20.0) | < 0.0001 |
| 40–64 years, n (%) | 1119 (58.3) | 698 (61.6) | 460 (59.1) | 249 (47.4) | < 0.0001 |
| 65–74 years, n (%) | 219 (11.4) | 144 (12.7) | 127 (16.3) | 112 (21.3) | < 0.0001 |
| 75 + years, n (%) | 102 (5.3) | 75 (6.6) | 64 (8.2) | 59 (11.2) | < 0.0001 |
| Gender | |||||
| Female, n (%) | 1156 (60.2) | 607 (53.5) | 391 (50.2) | 315 (60.0) | < 0.0001 |
| Diabetes, n (%) | 419 (21.8) | 260 (22.9) | 193 (24.8) | 144 (27.4) | 0.0387 |
| Hypertension, n (%) | 1386 (72.2) | 864 (76.2) | 551 (70.8) | 331 (63.1) | < 0.0001 |
| Weekly Kt/V | 2.1 (0.5) | 2.1 (0.4) | 2.0 (0.5) | 2.0 (0.5) | < 0.0001 |
| Weekly CCr (L/week/1.73 m2) | 60.0 (18.7) | 60.6 (16.6) | 58.7 (17.6) | 54.8 (17.7) | < 0.0001 |
| eGFR at the start of dialysis (MDRD) | 5.0 (2.4) | 4.9 (1.7) | 5.1 (2.1) | 5.4 (2.8) | 0.0007 |
| WBC (× 103/μl) | 5.8 (2.4) | 6.1 (2.3) | 6.3 (2.3) | 6.2 (2.7) | < 0.0001 |
| Hemoglobin (g/dL) | 10.2 (1.1) | 10.0 (1.1) | 9.8 (1.1) | 9.4 (1.3) | < 0.0001 |
| Ferritin (ng/dL) | 170.9 (76.7) | 388.4 (56.1) | 622.5 (83.2) | 1220.4 (405.8) | < 0.0001 |
| TSAT (%) | 27.4 (9.1) | 30.7 (8.2) | 33.0 (9.2) | 40.7 (15.2) | < 0.0001 |
| Serum calcium (mg/dL) | 8.9 (2.0) | 9.1 (1.8) | 9.0 (2.0) | 8.9 (2.0) | 0.3013 |
| Serum phosphate (mg/dL) | 5.2 (1.0) | 5.2 (1.0) | 5.1 (1.0) | 5.1 (1.2) | 0.0250 |
| Alkaline phosphatase (U/L) | 101.9 (55.3) | 109.6 (58.4) | 110.3 (56.9) | 116.7 (60.2) | < 0.0001 |
| Intact-PTH (pg/L) | 295.9 (250.9) | 292.8 (239.8) | 278.8 (256.3) | 256.8 (231.5) | 0.0080 |
| Uric acid (mg/dL) | 7.0 (1.3) | 7.0 (1.2) | 7.1 (1.2) | 7.0 (1.4) | 0.2876 |
| Cholesterol (mg/dL) | 199.7 (38.2) | 198.8 (35.1) | 196.5 (36.3) | 199.0 (40.8) | 0.2496 |
| Triglyceride (mg/dL) | 168.3 (98.1) | 184.0 (109.2) | 196.0 (110.3) | 227.6 (137.6) | < 0.0001 |
| nPCR | 0.1 (0.3) | 0.1 (0.3) | 0.1 (0.3) | 0.1 (0.3) | 0.0030 |
| Albumin (mg/dL) | 3.8 (0.3) | 3.9 (1.5) | 3.8 (0.4) | 3.7 (0.4) | 0.0021 |
| ESA dose, (U/month) | 16,124.0 (8277.8) | 16,803.5 (5777.1) | 16,724.4 (6973.2) | 17,167.0 (6176.0) | 0.0064 |
| Iron IV, n (%) | 1039 (54.1) | 620 (54.7) | 301 (38.7) | 121 (23.1) | < 0.0001 |
ESA: erythropoiesis-stimulating agent; eGFR: estimated glomerular filtration rate; IV: intravenous; nPCR: normalized protein catabolic rate; PTH, parathyroid hormone; TSAT: transferrin saturation; WBC: white blood cell counts. All values are expressed as the mean (SD) unless otherwise specified.